It is known to provide a tansportation vehicle, as disclosed in U.S. Pat. No. 3,312,180 of E. O. Mueller and U.S. Pat. No. 3,672,308 of W. R. Segar for a mass transit system, with the vehicle being automatically controlled by a vehicle control system and self-steering along a roadway having spaced track surfaces and a centrally positioned vehicle restraining I-shaped guide member. The vehicle includes a guidance apparatus consisting of a plurality of guide wheels for each drive wheel axle and engaging and locking-on of the vehicle ot the I-shaped central guide member, as shown by an article published in the Westinghouse Engineer for July 1965 at pages 98 to 103 entitled "Transit Expressway--A New Mass Transit System". The guide wheels are coupled to each drive wheel axle housing, such that the axle with its associated drive wheels and the vehicle will be steered by the guide wheels as the vehicle moves along the roadway.
The transportation vehicles can utilize dual support tires as shown in above U.S. Pat. No. 3,312,180 to provide a redundant vehicle support mechanism and to prevent the immediate stoppage of a vehicle or a train of such vehicles caused by a flat or delfated tire. Even with dual support tires, a frequent inspection of same is required to detect loss of air from one of the dual tires which could eventually lead to a dual flat.
As shown by the above cross-referenced patent, it is known to provide the power collection rail apparatus above the central guide beam. Should a vehicle flat tire condition occur with the supported vehicle axle and other associated portions of the vehicle then dropping down closer to the top surface of that guide beam, an undesired disturbance and even physical damage to the power collection rail apparatus could result with an attendant lengthy shutdown of the transportation vehicle operation along the roadway and even the whole mass transit system.